When an auth instance is deleted, disable it as a parent authority

[Aaron Wells]

Scenario:

1. Create an "Internal" auth instance (or any auth instance type, it doesn't really matter)
2. Create an XMLRPC auth instance, and set the Internal instance to be its "Parent authority"
3. Drop the Internal auth instance

Expected result: The XMLRPC auth instance should switch to having no parent
Actual result: The XMLRPC auth instance will *say* "None" if you look at its config (and throw a PHP warning) but in the DB it will still be configured to have the deleted internal auth instance as its auth instance

This situation causes a number of problems. The one I'd noticed before was that PHP warning on the XMLRPC auth instance page, which is because pieforms is trying to set the default to be the name of the auth instance that no longer exists. But the bigger problem (as seen here https://mahara.org/interaction/forum/topic.php?id=5627&offset=0&limit=10#post24259 ) is that it can cause problems when it tries to auto-create or auto-update user accounts from the child authority.

I think most admins would expect the XMLRPC instance in this case to simply lose its parent authority, not have to go in and manually save an apparently unchanged form instance in order to delete it.

[Aaron Wells (u-aaronw)]

https://reviews.mahara.org/2424

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/2424
Committed: http://gitorious.org/mahara/mahara/commit/82cef15376d38eca8c84c37f18a4bb725826c348
Submitter: Robert Lyon (<email address hidden>)
Branch: master

commit 82cef15376d38eca8c84c37f18a4bb725826c348
Author: Aaron Wells <email address hidden>
Date: Wed Aug 21 11:38:48 2013 +1200

Unset deleted institutions as parent authority to other institutions

Bug1214647

Change-Id: I03a365c4bfb25cd69a8ca83293bf25ed53ca1234

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/2574
Committed: http://gitorious.org/mahara/mahara/commit/6cde02ab80c60e6831d2435fd4c68b64994b63ec
Submitter: Son Nguyen (<email address hidden>)
Branch: 1.7_STABLE

commit 6cde02ab80c60e6831d2435fd4c68b64994b63ec
Author: Aaron Wells <email address hidden>
Date: Wed Aug 21 11:38:48 2013 +1200

Unset deleted institutions as parent authority to other institutions

Bug1214647

Change-Id: I03a365c4bfb25cd69a8ca83293bf25ed53ca1234